Apparatus for producing cap screws and the like



. I k v i I I I 3 5 I n 5 'flfifla I Feb. 25, 1930. WAYNE 1,748,503

APPARATUS FOR PRODUCING CAP SCREWS AND THE LIKE Filed Npv. 4, 1926 4Sheets-Sheet 1 avwenboz Feb. 25, 1930. G. H. WAYNE 1,748,503

' APPARATUS FOR PRODUCING CAP SCREWS AND THE LIKE Filed Nov. 1926 4Sheets-Sheet 2 Feb. 25,1930. H, W Y 1,748,503

ARATUS FOR PRODUC NG CAP SCREWS AND THE F'il Feb. 25,1930. v v a. H.WAYNE 1,743,503

APPARATUS FOR PRODUCING CAP SCREWS AND THE LIKE Filed Nov. 4, 1926 .4Sheets-Sheet 4 I avwwntoz 951 A flaw/" W gas 1 Patented Feb. 25,1930

. ITED sr Q GLENN'H. WAYNE, or WATERBURY, CONNECTICUT, ASSIGNOR ro"sCovILL MANN- TETS PATE NT-"JQOF-FICE1 1 FACTURING- COMPANY, OF ATENURY, CoNNE 'riCU'r, A COBPORATIONOF CON:

APPARATUS-FOB raonuome AP SCREWS AND THE LIKE I Application filedNovember 4, 192e. seriaiNo. 146,039. 1

,This invention relates to apparatus for producing; cap screwsand ;thelike.

Cap screws as known in the trade ordinari-i 1y comprisea'heXagonal,-fil1ster,flat or round head, a' threaded shank and anunthreaded portion between the s'hank and head which may be termed ashoulder. This shoulder has of smaller diameter is rolledibetween two adiameter-equal to theoutside or crest diameter ofthe threaded shank.

According to knownpractice a blankhavinga shoulder of final diameterandas'hank' V threading dies to thread the During' this threadingoperation a burr is. formed beyond the final turn of thethread and thisvburr is then rolled down to shoulder diameter .by means of planishingblocks; I

Apparatus for thread rolling asjheretofore known includes verticallymounted thread-Q ingd-ies having, above the serrated portions; planesurfaces Corresponding to theshoulder .Of thebm k. [These-surfaces areso dimensioned that the blanks can be suspended fromthe edgesof the dieblocks to properlyposition them for the thread-rollingoperation, In thecase of "ordinary, commercial cap' screws, the shoulderfor agivensizescrew has a given length but thetotal length varies in accordance withcommercial requirements. so

In thecase of special standardsrequired by the trade,"'however, thethread length for a i I screwxofgiven diameter is constantso that theshoulderlengthvaries with the total length.

" It is'an objectof the present invention to provide improved apparatuscapable of efiecti jely and economically producing cap screws bythethread-rolling. method.

f In the drawings l i .7 i Figure 1' is a top'plan view of apparatus for{It is a further object f provide apparatus of, the type mentioned/foreffectively and economically producing 7 cap variousforms screws having.various shoulder lengths. c With-these general ob ects, and others, 1nView, the, lnventiongfconsists,1n the features,

combinations, detailsof construction and ar-' rangements of parts: whichvwill'fir'st be described in connection with the accompanying V drawingsand then pointed out particularly inthe Claims.

the invention to and,

ance with the invention; I Figure 2 is an end vi shown inFig. 1; 1

Figure?) is aface' view of a threading die and planishing die inassembled relation;- Figured is an edge view thereof; d:Figure 5'; is anend view of ,th plani 1e; 1 Figure Gis. an end view ot the threadingFigure portionofthe threading die; Figure'8 is a view taken at'producingcap screws constructed in accordvthe die threadsandfthroughthe blank after thethreads have been form'ed upon the blank dies andalso showing the planishingblooks in operation; r

' Figure '11 is mediate blank; a Figure 12.is ,a similar view oftheblank threaded but unfinished; i f

Figure 13 is a similar view ofithe finished. product; V i

Figure I and a combined positioning and p'lanishing vention; I.

Figure 15 is an edge view th l' f s i g tions; 7 I A Figure 16is an endview o'fthe'die and poright angles: to v 7 is anenlargedsectional view.ofa

14 is a face viewof a threadingdie butibefore the planishingoperation'has been" performed; J .11. V,

Figure 9 is a similar viewbutshowing both ,'Figure 1.0 1s a side view ofa-rough blank; 1

a similarfview of aninter- 86 die in accordance .with one form'of. thisinp sitioning andplanishing block shown in 14.1nounted-inthe apparatus ot -Figs 1 and 2;

Figure 17 and1 8 are perspeotive'views-ofdies. 1 ,1

Referring to thedrawings, Fig. 13"-illustrates one example of-a finishedcap screw.

of positioning and planishingy comprising a shank having athreaded'portion 22', an 'unthreaded shoulder 23',and ahead 21. The apparatushereinafter described is capable of produclngsuch cap screws,- havingshoulders. ofttrue diameter and of proper finish and in which thethreadsterminate ance and strength, a cut-thread product.

According to the present invention, briefly stated, a blank is so formedand the blank is v so threaded that the final turn of the threadadjacent to the shank has full crest diameter.

Beyond the final turn of the thread the metal of theblank is upset inthe form of a ridge or burn which, after threading, is removed.

And at some stage in the procedure the shoulder is machined to size. Incarrying out the invention according to what isnow considered the bestplan of operation, the shoulder is machined before die-rolling, and theburr is worked into a prolongation of the shoulder to carry the shoulderdown to a thread turn of full outside diameter.

In carrying out the invention, along the lines stated, the finishedproduct referred to maybe formed from a rough blank such as is shown,for example, in Fig. 10. This blank has an unfinished round head 21%, ashank 22, and a rough finished shoulder 23 which is somewhat oversize asto diameter and undersize as'to length. Between the shank and shoulderis a bevel 24, hereinafter more fully referred to. This blank may beformed in any suitable manner, as by forging from round: stock in aheading machine. The head .21 is finished, as by millingor'die-cuttting, to

form the desired head. a Fig. 13 shows a filister head but the head maybe polygonal, fiat or round, the headfinishing being a wellknownoperation and formingno part of the present invention. The shoulder 23is mas chined, i. e.cut, to true final diameter, thus giving it thedesired finish and accurate size. This machining of the shoulder mayconvenientl v be done when the head is machined to trim the top andbottom. thereof.

The above described operations provide what may be termed anintermediate blank,

such asillustrated in F ig. 11. This intermediate blank has a finishedhead 21", a shank 22 and a shoulder 23 which is finished tothe -wil'l bethrown outwardly in rolling the final diameter but is somewhat undersizeas to length. The total length of the intermediate blank isapproximately the length of the screw when'finished. The difierence indiameter between shoulder and shank equals the amount by which the metalof the shank Between shoulder and shank is a The angle of the bevel andthe dethread. bevel 24".

ficiency in stem lengthare hereinafter re ferred to.

This intermediate blank is die-rolledto thread the same, the threadingextending alongthe shank and part way up the bevel, the extent beinghereinafter more fully referred to. Thisdie-rolling operation is such asto upset the rolled metal into the form of a thread, The metal of'theblank is caused to flow outwardly to form the thread crest, the

outside diameter of which is approximately that of the finishedshoulder. During the rolling operation described, only that part of theblank that is to be threaded is die-rolled, the shoulder and upper partof the bevel being left free. During threading, some of the metal of thebevel of the blank is caused to be upset and displaced outwardly intothe form of a ridge or burr beyond the final turn. of the thread.

Fig. 12 illustrates this stage of the production. The uncompleted' screwthere shown has a threaded shank 22 and an unthreaded shoulder 23".Beyond the final turn of the thread, adjacent the lower end of theshoulder is a ridge or burr25 slightly greater in diameter than theshoulder. The shoulder, for the most part, remains unchanged but theremay be av slight, enlargement of its lower end due to the crowding ofthe metal in forming the burr. Should this occur it is corrected whenthe burr is removed, as later described. t

The invention in its entirety includes two complementary threading diesbetween which the blank rollsas the thread is formed. As shown as anexample in Figs. 1+7, slidable in. upper and lower tracks 31, 32 of abed block 33 is a slide 34 having a die-carrying portion 35. This lattercarries a flat, substantially rectangular die block 36 which rests on aledge 37 of the carrier and is secured in place by means of clamps 38and bolts 39.

'The outer vertical face of the die blockhas a series of threading teeth40 hereinafter referred to. To reciprocate the die block 36,

in the embodiment here illustrated, secured to'tl e slide 34 is the endof a pitman 41 driven from a rotary disk 42 by a crank pin 43 mountedtherein. Disk 42 isconnected with a gear 44 meshing with a pinion 45 ona drive carried by the frame or bed block is an adjustably mountedsupporting block 51. This block has a ledge 52 on which is supported a,die block 53 heldin place by clamps 54 211K bolts 55 and arranged-on alevel with die 36 (Fig. 2). The outer vertical face of the die block 53is formed with a series of, parallel rectilinear teeth 56 running.endwise of the block but at an angle to the longitudinalaxis thereof.The teeth 40 of die 36 are similarly arranged, the teeth of one die,however, being opposed to the intervening grooves'of. the-other die, Aswill be understood by those skilled in the art, the angle of the dieteeth 6 V with respect to the liHeof-traveI of the blank,

governs the lead of the thread formed; In

theapresent embodiment,- the vtwo die blocks are located substantiallyparallelf and so spaced apartthat the toothcrests are separated by adistance'less than, and the groove bottoms by a distance 'greater than,the di- I a'ineterof the shank of theblank to be threaded. I That is,the groovebottoms, which. determine the thread .crests,;are'- spacedaparta "distance'approximatelyequal to the diameter 7 of'ithe desiredproduct," The position of die block {36 maybeadjusted by the use ofshims.

' Die block 53 may be adjusted by adjustment of the supporting block 51by means ofbolts 57 and by the use of shims. In the'embodiment shown,the die blocks are formed with teeth on both faces'so that the blocksmaybe reversed as one setof teeth wears out but,

for the purposes of the present description, only one toothed face needbe considerd. To facilitate the entrance of the blank betweenthedies,vthe opposingends are sloped or roundedoif as appears in Fig. 4,giving, in effect, a bell mouth entrance for the blank. f :In. theapparatus here shown as an ,example, the ends'of the die teeth along thesides of the dies toward the blank head-or what may be termedthetrailing ends of the die teethare ground or chamfered ofi at an angleto theplane of the tops of the teeth (Figs. 6, 'Zand 8). While onepurpose of'so' chamfering the dies is to prevent the teeth I o fromchipping and breaking off at the trail structioncooperates convenientlywith the bevel of the blank in the formation of the ing ends duringthreading, -such a die condesired product. I I mWith'the movablediedrawn back to the end of its idle stroke 1), a blank is pofsitionedadjacent the opposingends of the complementary-dies. It will be apparentthat theblank must beso positioned above the die teeth that the shoulderwill be bjeyond thei teeth. The reiis provided' means for fixingtheposition'of the blanks with respect to the i (die teeth. This may beaccomplished, for,

. example, by a pair of complementaryledges associated with. the dieteeth and onwhich "the blank heads may, be suspended, these ledges beingso arranged, however, that .the

blank shoulders' are left freeduring th rolling. In vthe embodiment-illustrated in "Figs. 1 7-, the ledges'are formed as part of the twodie blocks. To thisend, die block 36 extends beyond the line oftermination of the f chamfered teeth-so that its top-cdge-formS a ledgefor receiving the head of-a blank.

- I The die blankr53 is similarlyformed to provide a ledge 61.These-complementaryledges receive the. underside of the head of theblank which is {thus suspended=.-between; the die blocks- {The ledges60, 61 are: spaced from the line: of termination "of their respective Idie teeth a }distance to cause the blank-to;

beso' positioned with respect to the die teeth that the desired pointongthe blank comes I opposite the line of 'termination of the teeth. I

As is known to those skilled inthe art, there is a tendency for theblank to jump endwise in the. direction of its head when theteeth takehold. Consequently, this jump is allowedfor. The amount of jump for agiven I set of dies being'known, the ledges 60, 61 are spaced from theteeth accordingly. The ledges initially position the blank, which thenjumps and thereafter it is 'held'in the same relative axialpositionbyithe inter-engage merit of the di e teeth and the formed thread.

Due to the extension. of the die blocks 36, 53 to form the ledges 60,61, the die blocks have plain surfaces '62, 63 that come opposite bevel.These plain. surfacesare soformed that when the die blocks areinposition the plain surfaces 62,- 63 are spaced apart a distancesubstantially greater than the-diameter the shoulderof the blank andpart of the of the shoulder of theblank. In terms-of one. die, its plainsurface is located below the plane-0f the bottom of the die teeth (Figs.7 and 8). Consequently, during the thread-rollingthe shoulder of theblank is left free. In otherwords, the surfaces 62," I

63 playno part in the threading operation except in that the ledges60, 61 initially position the blanks. I 1

A. blank being suspended in position, as a above described, the. movingdie 36 is ad vanced and the blank is rolled between the two dies.Thatis, the blank revolves on its between the dies own axis and travelsalong I I I as the moving die advances.- For a half turn of-Qthe' blankthe teeth of die 36 form thread v v teeth digging into the metalto 'formthe threadgroo'ves and displacing the metal outwardly into the diegrooves to form the thread crestmDuring the next halfj turn of the blankthehalf thread portions formed by die 36jarepresented to die 53 and thehalf thread portions formed by .die are presented to die 36 for furtherformation 7 or finishing orzboth. 1 With the apparatusdescribed, "thecomplete thread, is roughly" ",formedduring the first, half turn or fewhalf:

portions in half the surface of the blank and theteeth of 'die 5 3 formthread portions in v the other half of the blank surface, the die Iturns of the blank, the remainder of the action'being 'inthe nature of afinishing or planishing foperation. Duringthis thread-,

ing operation, the chamfered portionsof the die teeth, acting on the.bevel of the blank,

thread partof the sameyand upset some of the metal into the form of aridge'or burr beyond the 'finalturnof the threa'd'.- Fig, 8

grooves to form the thread crest. Fig. 8 also illustrates howthe-chamfered ends of the die teeth have threaded part ofthe bevel andhave upset the metal into a burr 25 beyond thefinal turn of the thread.

The invention in its entirety includes platens for rolling down the burrto stem diame ter, these platens being freely separated from andindependent of the threading dies. The

platens may, for example, alsobe formed as part of a second die blockhaving'a spacing portion and a platen portion. In the exemplifioationillustrated in Figs. l-9, there is provided a pair of complementaryplaten die blocks 72, 73. These are rectangular blocks of the sameheight as the threading die blocks. The platen die block72 is mountedalongside of threading die block 36 and the platen die block 73alongside of threading die block 53. The two platen die blocks are heldin their respective die carriers by clamps 7d and 75 like the clampswhich hold the threading die blocks and may be adjusted by shims. At thetop of platen die block 7 3 is a platen 71 (Figs. 3 and 4) formed as apart.

of the block, being thicker than the remainder of the block. This platenhas its front face substantially in the plane of the bot toms of thegrooves of the adjacent thread ing die. In width, i. 'e., verticalwidth, the platen extends down'to a line substantially below the line oftermination of the teeth of the adjacent threading die (Fig. The platenlength is sufficient to enable it to act on a blank during one or morerevolutions thereof. The remainder of block 7 3 is a spacing portion.That is, it serves to space the platen portion from the ledge of the diecarrier.

Die block 72 is an oppositely facing duplicate. That is, it has a platenportion 70 like platen 71 and a spacing portion like that of block 73.

When the two platen die blocks are opposite each other (Fig; 9) theplatens 70, 71 are spaced apart a distance substantially equal to thediameter of the blank shoulder.

As appears in Fig. 3, when the platen blocks" are in placethe-platens'are in line with the plain surfaces 62,63, but they arewider than the latter by. the widtl' of several die teeth. That is, theplatens are arranged to come opposite the blankshoulders and severalturns of the thread. The platensurfaces are arranged parallel to theplane of the tops of the teeth except that they are slightly sloped off(Fig. 4) at theend toward the die blocks to facilitate entrance of theblanks. V

As the slide 3% moves across carrierbl, and near 'the end of the stroke,platen 70 moves across platen 71 and part of the blank is rolled betweenthem (Fig. 9). rolling operation the upset metal of burr 25 is rolleddown by the platens, the displaced During the metal being received bythe final turn of the thread That is, the metal is worked into theshoulder to prolong the same,'carrying the shoulder down to a threadturn of full outside diameter. If the shoulder. 23 of the partly formedblank is increased in diameter'as above referred to, it will have truediameter after the rollingby the platens. F

Except in positioning the platens, the blocks 72, 73, other than theplaten portions play no part in the operation. As the distanceseparating the faces of the spacing p'ortions of the blocks is greaterthan the diameter of the blank they obviously do not touch the blanks.

9 illustrates the relation of the parts near the end of the platenaction. The burr 25 has been rolled down, the displaced metal beingreceived by the final turn of'the thread and elongating the shoulder,which extends down to a thread turn of full outside diam eter.

It is considered advisable to have the platens extend downwardly somedistance beyond where the burr is encountered. Theoretically the platensurfaces are tangential to the thread crest but if it is found that theplatens tend to flatten the thread crest, the platen surfaces may beground oif adjacent the lower edges to avoid this.

As the moving die reaches the end of its rolling stroke the blankreaches the endof the stationary die and can drop out, to be collectedas desired. The moving die then makes an idle returnstroketo'initial'position,thus completing the cycle of operations for oneblank. V

. Referring back to the blank, it is noted that the bevel 24 abovereferred to need not necessarily be a true bevel. That is, the surfacemay be frustro-conical or may be slightly rounded. WVhat is desired is agradual step down from shoulder to shank of such dimension that the dieswill upset such a burr as can'be worked into the shoulder to prolong thesame as described. For-convenience, however, the term bevel has beenused. The angle of the bevel is not the same for all blanks. Generallyspeaking, the angle of bevel varies with the diameter of blank and withthe depth of thread to be formedi As it is difficult, even with thesevalues known, to fix a standard, it is considered advisable to adopt agivenbevel and make'a trial'run. .It has been-found that for screwsvarying'in diameter from 1/ to 7 /8; a suitable range of included bevelangles is' from 20 to 30. This range provides a starting point for agiven production run, correction being made it necessary, after a trailrun, as later described. As the diiferencein shoulder and shank diameterfor a given size screw and given dies is fixed, the fixing of the bevelangle, of course, determines the-axial length 7 of the bevel.

150 I I While the shoulderof" a given standard ing thedieteeth to changethefangle'of 'cham The angle of chamfer 'of the 'die teeth varies,generally speaking, with the. angle'of Q the bevel. Forthe-abovementioned range 'of'screws, a suitablelrange of chamfer angle 1 is 259to As a starting point fora given run, the die blocks areconvenientlyformed so that-the blank is positioned in rolling to 1 causethe "threading to extend about two I thirds of theway' up the bevel.

' 1 As anexample, the] following'dimensions and relations have beenfound Suitable for the production'of 1/2. stee1"cap screws, all figuresbeing approximate '--Diameter o-f shank'o f blank ('22), 7 16".

i Width of pl ainsurfac'es (62, .63) separat- Diameter ofshoulder-(after machining) Axial length or bev1 j,(24), 5 32"; (This ILength of shoulder of screw produced (23) at opposite point incircumference, 1/2" size should have Tthesta'ndar'd length at all ipoints, aslight overl ength"ztt'sorriepointsis A i V 1 products.

immaterial. Variation, such as that above mentionedfrom agivenI shoulderlength to a slight overlengthis alsofound in cut thread As unknownvariables, such, for example,

as 'the nature and condition of the stock.

amy. cause a slight deviation in' results, it may be necessary to make areadws'tment following atrial run, (This may befdone,

for example. by changing the angle of the bevel of the blank andof the'chamfer of the dies, if they are chamfered. 'Orit may be 'accomplishedby a variation in the axial posi tion of the blank with respect to-thedie teeth. That' is, if the bevel of the blank istoolong for a," givendie,'too great aburr is formed. This may be corrected by regrindfer, orby using other blanl zsg If the bevel of the blankis too short foragiven die, there is not enough of a burr formed; This may be correctedvby new dies, new blanks, or by grinding down the ledges of the dies(60, 61) so "as to so position the blanksthat the thread- 7 ing extendsfurther up the bevel, more metal 6 z thus being upset into the burr.

With the apparatus describ d it is possible to utilize theeconomicalstep of threading the 'blank by die-rollingat the same timeproducing a cap' screw that has the appean an'ce and strength'of acutethrjead 3roduct.: Further, the partsdescribed permit thread rollingand' planishirig in ta-0a 'a sagetr. the blank and, as threading. dieswear out, the same platen blocks maybe used, it being nee:

'essary to make new dies only. Further, the threading dies shown areeconomically cut,

being plain rectangular blocks. Y 2

" The'embodimentof the-{invention above 7 described isparticularlyad'aptable to producing the. ordinary trade pro'duct,"abiovereferred'to, in which the shoulders have.

given length forgiven sizes, theshanksvary- 'ing in length. i A givenpair of dies may pro duce cap screws of any total length upto the widthof the dies, the shoulders, however, being necessarily of the samelength.

illustrated in Figs. 1fl'18 inclusive, particularly' adaptable to theproduction of, cap

' A further embodiment of the invention is 1 screws of the special tradestandard above referredto, i. egin which the screws of a given lengthvaries, the length of the shoulder must varyp V" In the; embodimentreferred to, provision is'lmade' for a variable.blank-positioning meansfor a given "threading die. As here shown as an example,.a thread ng dieis provided which is generally like the die 36 and diameter always havethe same'thread length regardless of their total length- In thejcase ofthese screws, therefore, as the total isadapted to be moun'ted by clamps38 [(Fig. 3 I

16) in-the same machine as above described;

Separate blank-positioning blocks of differ ent heights are provided' sothat when the machine is used to produce a screw ofone ice I givenlength, one size of theseblocks islassociated with the threading diesand when another'length of screw is to be'produced another set ofblank-positioning blocksis' substituted. This permits; using the 'same'threading dies to produce screws in which the shoulders have difierentlengths. fThe die comprises a generally rectangular block 101 (Figs. 14and 16) of substantiallylthe same thickness as die 3b..v The block hasare, similarly chamfered. the -rear'end of the die blocklOl the top andbottom faces are r'abbeted (Fig. 14) for a purpose later described. A"complementary die 102 is pro vided having teeth like die block 53,similarly' chamfered. This die'block is also rabbeted on: its top andbottomfa'ces. In the die blocks 101, '102, the blocks terminate at thechamfers. In other words, the :die blocks haveno extension 'along'theirupper sides formingledges as in the case of the dies pre viouslydescribed; i Thereareprovided platen means for rolling down the burrformed during threading 1 and separate'mea'ns capable of'substitution plfl't 7 width sufficient for the screw to-be produced. and in length itequals, as 'shown, the threadingf die 36 plus the'plate'n' block. Thedie 101 is formed with threading teeth inthev same manner as the-die 36and these teeth for positioning the blanks'with respect to the dies.This may be conveniently acco1nplished by interchangeable blocksindependent of the threading die and combining both positioning ledgesand platens.

In Fig. 17 is shown a block 103 provided for this purpose. It isarranged to fit over the threading block as shown inFig. 14, therabbeted part of the top face of block 101 engaging the rear enlargedportion of block 103. The two blocks are held in the machine by clampsin the same manner as the die blocks 36 and 53 were held. A similarblock 103 is provided for die 102. It will be seen that the portion ofthe blocks 103, 103 to the left of line X-X are blank-positioningportions and that the parts of .the blocks to the rightof line XX areplanishing portions. As shown in Figs. 1-9 inclusive, the planishingblocks or dies are spaced apart a distance equal to the diameter of thestem so as to roll down the burr formed in threading. On the other hand,the blank-positioning portions of the dies shown in those figures arespaced apart so that during threading they will not make contact withthe stem. Inother words, the blank-positioning portions and the plan.ishing die are not in the same plane. In the form of block shown inFigs. 1418, inclusive, it is noted that the faces of the blocks 103, 103are plane surfaces. Consequently, the blocks 103, 103 are slightlyshifted in the horizontal planeso that, their outer faces are inclinedto the line of travel of the blank, the pivot point being somewhatadjacent the line XX (Figs. 14 and 15). Consequently, during thethreading operation, the shoulder of the blank will not be engaged byblocks 103, 103*, to the left ofline XX but, when the blank arrives at aposition near the line V XX, the stem will be engaged by the slightlyconverging faces of the two blocks (to the right of the line X -X), sothat the burr will be rolled down as the blank finishes its rollingmovement.

It is to be noted that'block .103 mayalso be positioned in a similarmanner with respect to the lower face of block 101, the rabbeted part ofthe latter being provided for proper fitting. This permits of die 101being used in reverse position. 7

. Figure 15 shows the angular relation between the blocks and thepositions of the cap screw 22 during the threading and planishingoperations. It will be apparent that the angular shift given the blocksis'only slight, the

precise angle being found by experiment.

If desired, the blank-positioning and planishing blocks may be made intwo parts, the line of division therebetween extending along line XX.For convenience in manufacture they are preferably formed as one.

In Fig. 18 shown a block 104 having a blank-positioning portion 105whose width is different from thatof block 103. This block,

and its complement, may be substituted in placeof blocks 103, 103 whenit is desired to alter the overall length of cap screws, whilemaintaining the length of threaded shank the same. That is, when it isdesired to thread other blocks, such as blocks 10 1, are substituted.Blocks 104C, for example, being smaller as to vertical height thanblocks 103, 103, serve to properly position a blank having a shortershoulder with respect to the die teeth. With this construction capscrews having dif ferent shoulder lengths maybe threadedin the same diesmerely by substituting different positioning blocks. 7

The operation of the apparatus will be clear from the above withoutfurther description.

lVhat is claimed is: I v v 1. In apparatus of the class described, andin combination, two complementary threading dies for threading acapscrew blank and causing, during threading,;the formation of a burr onthe blank beyond the-final turn of the thread, two complementaryplanishing dies for rolling down said burr and working the metal thereofinto the shoulder of the blank to elongate it, said pla-nishing diesbeing .freely separable fromthe threading dies, and

means for causing relative movement between the threading dies andbetween the planishing dies to cause a blank to roll therebetween. 2.Inapparatus of the class described, and in combination, twocomplementary thread ing dies for threading a cap screw: blank andcausing, during threading, the formation of a burr on the blank beyondthe final turn of the thread, die carriers in which said dies are I 3.In apparatus of the class described, and

in combination, two complementary threading dies for threading a capscrew blank and causing, during threading, the formation of a burr onthe blank beyond the final turn of the thread, die carriers in whichsaid dies are mounted, two blocksalso mounted in said carriers andhaving a width substantially equal to the width of the threading dies,said blocks having formed thereon two complementary planishing platensfor rolling down said burr and working the metal thereof into theshoulder of the blank to elongate it, and means for causing relativemovement between said die carriers to cause a blank to roll between saiddies;

4/ In apparatus of the class described, and

in combination, two complementary threading dies for threading acapscrew blank and V a cap screw with a ClllIGI'QIlt shoulder length,

o f -causing, during threading, the formation of "a burr on the blankbeyond'thefinal turn of the thread, die carriers in which said dies arer I mounted, two complementary planishing platens for rolling downsaidburr and work-- ing the metal thereof intothe shoulder of 7 the blank toelongate it, separate die blocks I having a width substantially equal tothe width of the threading dies and on which said platens are carriedand which are also mounted in said carriers, and means for causingrelative movement between said die carriers to cause theblank to rollbetween the I said dies. a

5. In combination, a die carrier comprising (a ledge, a threading' dieblockmounted on tated to be assembled with said threading dies to formledges for positioning blanks at predeterminedrelative positions withrespect to'the threading dies.

In testimony whereof, I have hereunto set my hand. i I

GLENN H. WAYNE.

end of the first die block, the second die block I having a'planishingplaten located substantially in the plane of the bottom of the die lowthe terminal line-of the die teeth. ,6. In"combinat1on,' means forthreading and planishing a cap screw blank "compris- .fitheendsthere'ofbeing chamfered, a second ing in part a block having 'a'series of teethteeth of the first die, the platen extending be unthreaded block mountedon said first block. 7

and means for positioning said second block so that it forms ablank-positioning ledge with re'spect to one portion of said first blockand "a 'planishing surface with respect to another portion thereof. I

7; In an apparatus for forming cap screws 7 having a threaded shank andan unthreaded shoulder, complementary'threading dies for 'forming'athread on blanks rolled therebetween, and separate complementary blockscapacitated to be assembled with said thread- Z-ing dies to formblank-positioning ledges, said blocks, whenassemble'd, having planesurfaces betweentheledgesfand the threading dies lyingin aplane belowthe plane of. the bottom of the die teeth, whereby a p'ortion of theblank isleft free during rolling, f 50 said blocks being readilyremovable from the dies for substitution of interchangeable blocks of"different dimensions, whereby blanks may be positioned in differentrela tive positions with respect to the threading dies.

8. In combination, oo-operating threading dies forv forming a threadonia blank rolledv 1 therebetween, and regulable means for providingblank-positioning ledges, associated with the threading dies, wherebyblanks may be positioned at different relative positionswith respecttothe threading dies. 7

' 9. In combination, cQ-Operatmg threading dies for forming a thread onablank rolled therebetween, and; regulable blocks capaci-

